Particulate material conveying apparatus

ABSTRACT

Particulate material conveying apparatus, e.g. for conveying powder paint from a container to a spray gun, has a gas flow passage extending past an inlet, and a vibrator for vibrating the inlet to counteract clogging of the inlet. The vibrator comprises a ball driven around a circular race by compressed air, which is thereafter discharged from the vibrator into the gas flow passage to entrain the particulate material into the gas flow passage through the inlet.

United States Patent Vertue Feb. 4, 1975 [5 PARTICULATE MATERIAL CONVEYING 1,031,289 7/1912 Pedley 302/25 x APPARATUS 1,971,123 8/1934 Tappen 1 302/25 X 3,035,737 5/1962 Speas 222/82 [75] Invento Char Vertue, Etoblcoke, 3,333,735 8/1967 Odasso 222/82 x Ontario, Canada 3,563,421 2/1971 Coates et a1. 222/196 [73] Assignee: Volstatic of Canada Limited,

O i C d Primary Exammer -Ev0n C. Blunk Assistant ExaminerW. Scott Carson [22] 1974 Attorney, Agent, or FirmSughrue, Rothwell, Mion, 21] Appl. 190.; 453,119 Zirm & Macpeak [30] Foreign Application Priority Data [57] ABSTRACT Jan. 16, 1974 Canada 190309 Particulate material conveying apparatus, for com veying powder paint from a container to a spray gun, [52] U.S. Cl 222/82, 302/25, 302/32, has a gas flow passage extending past an inlet and a 302/51, 302/561 222/196 vibrator for vibrating the inlet to counteract clogging [51] Int. Cl. B65g 53/14, B 67b 7/24 of the inlet The vibrator comprises a ball driven [58] held of Search 222/82' 302/25 around a circular race by compressed air, which is 302/321 51156-58 66 thereafter discharged from the vibrator into the gas flow passage to entrain the particulate material into [56] References the gas flow passage through the inlet.

UNITED STATES PATENTS O 914,783 3/1909 Boland 302/25 x 12 Clam, 4 Draw F'gures 5 20 I k J 21 33 22 A f is 56 5!. E 03 I 2 39 Q be 55 0 2 1B 1 B A 1 I FATENTED H975 3.883.808

SHEET 10F 3 Fig.7.

P/JENTEB FEB 41975 SHEET 3 OF 3 PARTICULATE MATERIAL CONVEYING APPARATUS The present invention relates to particulate material conveying apparatus, and to a method of conveying particulate material, and is useful in particular in connection with the conveyance of powder paint from a container e.g. to a spray gun for discharge into an electrostatic field or to an electrostatic spray gun.

It has previously been proposed to provide a particulate material conveying apparatus in which a flow of compressed gas travelling along a gas flow passage is employed to draw particulate material into the gas flow passage through an inlet passage opening into one side of the gas flow passage. A vibrator is provided for vibrating the inlet passage to counteract clogging of the inlet end of the inlet passage. Separate gas supply pipes are required to provide the compressed gas to the vibrator for operating the latter and to provide a flow of gas at high speed past the inlet passage along the gas flow passage.

It is an object of the present invention to provide a novel and improved particulate material conveying apparatus in which the need for separate compressed gas supply pipes for operating a vibrator and for entraining the particulate material is eliminated.

It is a further object of the present invention to provide a novel and improved apparatus and method for conveying particulate material by which particulate material can be extracted from a container, e.g. a plastic bag, without opening the container.

According to one aspect of the present invention, there is provided a particulate material conveying apparatus comprising an inlet for the entry of particulate material into the apparatus, a gas flow passage extending past the inlet, means for vibrating the inlet, a compressed gas supply passage communicating with the vibrator means for supplying compressed gas to the vibrator means to drive the latter, and the vibrator means having a compressed gas outlet communicating with the gas flow passage for discharging the compressed gas from the vibrator means along the gas flow passage past the inlet to thereby entrain the particulate material through the inlet into and'along the gas flow passage.

With the present apparatus, by employing the compressed gas discharged from the vibrator means to entrain the particulate material from the inlet and along the gas flow passage, only a single compressed gas supply pipe is required for operating the apparatus.

Preferably, the vibrator means comprise a ball race extending around and spaced outwardly from the gas flow passage, thus providing a compact assembly of the vibrator and the gas flow passage, and the gas flow passage is provided with a flow constrictor for increasing the speed of flow of the compressed gas past the inlet, the flow constrictor being in the form of a tube extending along the gas flow passage and spaced from the wall of the gas flow passage to allow the compressed gas to flow from the vibrator along the gas flow passage between the wall of the gas flow passage and the tube to an inlet end of the tube, at which a particulate material collecting space is provided for collecting any particulate material which may flow through the tube in a direction opposite to the normal direction of flow of the compressed gas through the tube during the operation of the apparatus. By collecting such particulate material in the particulate material collecting space, the

thus-collected particulate material is prevented from flowing back into the vibrator.

The gas flow passage may be formed by a tube extending through a body of the apparatus, the body being formed in two separate parts held together, with the'vibrator housed therebetween, by means of a projection on the gas flow passage tube bearing against one of the body parts and a retainer in abutment with the other body part and secured to the gas flow tube.

According to another aspect of the present invention, there is provided a method of conveying particulate material from a container, which comprises piercing a tube through the container and drawing the particulate material from the interior of the container through the tube and through an opening into a gas flow passage by discharging a flow of gas along the gas flow passage past the opening to entrain the particulate material in the gas flow.

Using this method, any need for a hopper for containing the particulate material is eliminated, and consequently the particulate material cannot be spilled during emptying of the particulate material from the container into the hopper. Thus, risk of contamination of the particulate material is greatly reduced, since the container, which may be a plastic bag or a cardboard box, remains unopened. When the particulate material is powder paint, rapid changeover from spraying of one colour to another is facilitated, since there is no necessity to clean out or replace a powder hopper.

The invention will be more readily understood from the following description of an embodiment thereof given, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 shows a side view in section through a powder paint container provided with a conveying apparatus for transferring powder paint from the container to a spray gun;

FIG. 2 shows a view taken in transverse cross-section through the conveying apparatus of FIG. 1;

FIG. 3 shows a plan view of the conveying apparatus of FIG. 2; and

FIG. 4 shows a side view of the conveying apparatus of FIGS. 1 to 3 employed to remove powder paint from a plastic container.

In FIG. 1, there is diagrammatically illustrated a particulate material conveying apparatus, indicated generally by reference numeral 10, embedded in an accumulation ll of powder paint, which is contained in a hopper 12. A pump P is connected to the conveying apparatus 10 by a compressed air supply pipe 13, and an outlet of the conveying apparatus 10 is connected by an outlet pipe 14 to an electrostatic spray gun 15 for spraying the powder paint onto articles (not shown) which are to be painted. The pipes 13 and 14 are flexible pipes, for example of rubber or plastic material, so that the conveying apparatus 10 can be readily re moved from the hopper 12.

The construction of the conveying apparatus 10 is illustrated in greater detail in FIGS. 2 and 3.

The conveying apparatus 10 has a body made of plastics material, for example nylon, and formed in two separate parts, namely an upper part 18 and a lower part 19.

A gas flow tube 20 extends through the body parts 18 and 19 and is formed with a radially outwardly projecting collar 21, which abuts a top surface 22 of the body part 18.

A retainer in the form of a cup nut 24 in threaded engagement with the lower end of the gas flow tube abuts against the bottom of the lower body part 19, so that the body parts 18 and 19 are secured together in mutual abutment by means of the gas flow tube 20 and the cup nut 24.

A ball race 27 is accommodated in a cylindrical recess 28 in the underside of the upper body part 18 and is thus housed between the upper and lower body parts 18 and 19. A ball 29 is free to roll around the ball race 27 and the ball 29 and the ball race 27 together form a vibrator, the purpose of which is described in greater detail hereinafter and which extends around and is spaced radially outwardly of the gas flow tube 20.

An O-ring 30 recessed in the top of the lower body part 19 and compressed between the latter and the underside of the ball race 27 serves to prevent rotation of the ball race 27 relative to the body parts 18 and 19 when the ball 29 is driven around the ball race 27, as described hereinafter.

In addition, a further O-ring 31 recessed in the top of the lower body part 19 and compressed between the latter and the upper body part 18 serves to provide a seal between the upper and lower body parts 18 and 19.

In a modification, which is not illustrated in the drawings, the two O-rings 30 and 31 are replaced by a single sealing ring recessed in the top of the lower body part 19 and straddling the underside of the ball race 27 and the underside of the upper body part 18.

A compressed gas inlet tube 33 is press-fitted into the upper body part 18 and communicates with a boring 34 in the upper body part 18, the boring 34 communicating in turn with a radial boring 35 formed in the ball race 27. The pipe 33 and the borings 34 and 35 form a compressed gas supply passage through which compressed gas is supplied, in the direction of arrows A, into the vibrator for driving the ball 29 around the ball race 27.

The side of the gas flow tube 20 opposite from the boring 35 is formed with an opening 37 which serves as an outlet for the flow of the compressed air from the vibrator into the gas flow tube 20, as indicated by arrow B. A flow constrictor in the form of a tube 38 extends along the gas flow tube 20 and is secured in position in the gas flow tube 20 by means of a grub screw 39 in threaded engagement with the wall of the gas flow tube 20 The flow constrictor tube 38 is formed at its upper end with an enlarged portion 40, which extends into engagement with the wall of the gas flow tube 20 and prevents the flow of the compressed gas between the constrictor tube 28 and the gas flow tube 20 past the upper end of the constricted tube 38.

However, the remainder of the flow constrictor tube 38 is spaced from the wall of the gas flow tube 20 to allow the compressed gas from the outlet opening 37 to flow downwardly and into the lowermost end 42 of the flow restrictor tube 38, as indicated by arrow C.

Beneath the lowermost end 42 of the flow constrictor tube 38, the cup nut 24 has a hollow interior which provides a powder collection space 43, the purpose of which is described hereinafter.

A powder inlet nozzle indicated generally by reference numeral 45 is formed with a threaded end portion 46 which is in threaded engagement in an opening 47 formed in one side of the upper body part 18.

The powder inlet nozzle 45 is formed with an axial boring 48 extending from the free end of the powder inlet nozzle 45 and communicating with the boring 49 which extends from the boring 48 to the end portion 46 of the nozzle 45 and which is of slighly larger diameter than the boring 48.

The boring 49 communicates with a boring 50 in the upper body part 18, which in turn communicates through a powder inlet opening 51 formed in the wall of the gas flow tube 20, with the interior of the gas flow tube 20.

The borings 48, 49 and 50 and the powder inlet opening 51 form a powder inlet passage for the flow of pow der through the nozzle 45 into the interior of the gas flow tube 20 as indicated by arrows D. The interior of the gas flow tube 20 forms a gas flow passage indicated by reference numeral 53.

The free end of the nozzle is formed with a frustoconically tapered outer surface 54 which converges with the wall of the powder inlet passage to form therewith a thin annular edge 55 at the mouth of the powder inlet passage in order to counteract build-up of powder at the inlet end of the powder inlet passage and thus to counteract clogging of the powder inlet passage.

The tapered surface 54 extends from the annular edge 55 to a relatively long cylindrical outer surface 56 of relatively small diameter, so that the outer end of the powder inlet nozzle 45 is of sufficiently small diameter and has a sufficiently tapered end, to enable it to be readily pushed through and to pierce the side or bottom of a powder paint container, for example a plastic bag or a cardboard box, as referred to again hereinafter with reference to FIG. 4.

The lower body part 19 is formed with a downwardly frusto-conically tapered undersurface 58 in order to allow the conveying apparatus 10 to sink readily into the accumulation of powder paint 11 until the conveying apparatus 10 is embedded or immersed in the powder, as illustrated in FIG. 1.

In operation of the above-described apparatus, the compressed air supplied by the pump P through the supply pipe 13, the outlet end of which is fitted onto the upper end of the compressed gas supply pipe 33 as illustrated in FIG. 4, passes through the compressed gas inlet passage in the direction of arrows A into the vibrator, and causes the ball 29 to rotate about the ball race 27, as mentioned above, which causes vibration of the whole of the conveying apparatus 10. The compressed air flows from the vibrator and into the constrictor tube 38, as indicated by arrows B and C, and is discharged from the upper end of the flow constrictor tube 38 as indicated by arrow E.

As can be seen from FIG. 2, the upper or outlet end of the constrictor tube 38 is opposite the powder inlet opening 51, and the discharge of the compressed air from the constrictor tube 38 as indicated by arrow E causes powder to be drawn in through the inlet nozzle 45 as indicated by arrows D and to be entrained in the gas flow along the gas flow passage 53 and thence, through pipe 14, to the spray gun 15.

The flow constrictor tube 38, by constricting the flow of the compressed air, increases the speed of flow of the compressed air past the powder inlet opening 51 and thereby assists in creating a sufficiently strong suction in the powder inlet passage to ensure that the powder is drawn in to the gas flow passage 53.

The powder collection space 43 serves to collect any powder which may flow downwardly through the flow constrictor tube 38 when the supply of compressed air is terminated and thereby prevents this backflow of powder from reaching and contaminating the vibrator and impeding the rotation of the ball 29. When the supply of the compressed air is again continued, any powder collected in the space 43 is drawn upwardly through the flow constrictor tube 38 by the flow of the compressed air.

In order to protect the relatively fragile powder inlet nozzle 45 from damage, the apparatus may be provided with a U-shaped guard 60 which, as illustrated in FIG. 3, has its free ends plugged into the upper body part 18 at opposite sides of the powder inlet nozzle 45. However, the nozzle guard 60, which for convenience has not been illustrated in FIGS. 1 and 2, may be omitted entirely.

FIG. 4 illustrates how the above-described apparatus, minus the nozzle guard 60, can conveniently be employed to extract powder from a container indicated generally by reference numeral 61, which is shown broken-away in FIG. 4 and which may, for example, be a plastic bag or a cardboard box. As shown in FIG. 4, it is simply necessary to pierce the powder inlet nozzle 45 through the container 61 from the exterior thereof, whereupon the powder can be readily extracted from the container 61 by supplying compressed gas through the pipe 13. It will be readily appreciated that, in addition to counteracting clogging of the inlet end of the power inlet nozzle 45, the tapered surface 54 and the thin annular edge 55 facilitate the piercing of the container 61 by the powder inlet nozzle 45.

The ball race 27 is made of hardened steel, in order to counteract wear of the ball race by the ball 29, and the gas flow tube 20, the cap nut 24, the compressed air supply tube 33 and the flow constrictor tube 38 are preferably made from a readily-machinable magnesium alloy although, of course, other materials may be employed for these parts, as will be readily appreciated by those skilled in the art.

The nozzle guard 60 is readily removable, by unplugging, from the upper body part 18, and the gas flow tube 20 is sealed to the upper and lower body parts 18 and 19 by O-ring seals 62, 63, respectively, recessed in the upper and lower body parts 18 and 19.

I claim:

1. Particulate material conveying apparatus, comprising:

an inlet for the entry of particulate material into the apparatus;

a gas flow passage extending past said inlet;

means for vibrating said inlet comprising a ball race extending around and spaced outwardly from said gas flow passage and a ball adapted to be driven around said race; and

a compressed gas supply passage communicating with said vibrator means for supplying compressed gas to said vibrator means to drive the ball around the race;

said vibrator means having a compressed gas outlet communicating with said gas flow passage for discharging the compressed gas from said vibrator means along said gas flow passage past said inlet to thereby entrain the particulate material through said inlet into and along said gas flow passage.

2. Particulate material conveying apparatus as claimed in claim 1, further comprising a nozzle, said inlet comprising an inlet passage extending through said nozzle from the mouth of said nozzle to said gas flow passage, the outer surface of said nozzle having an outer surface which is tapered and converges with said inlet passage at said nozzle mouth to form a thin annular edge around said mouth.

3. Pariculate material conveying apparatus as claimed in claim 1, wherein a constriction is provided in said gas flow passage for increasing the speed of flow of the compressed gas past said inlet.

4. Particulate material conveying apparatus as claimed in claim 3, wherein said constriction comprises a constriction passage extending along said gas flow passage to said inlet and having a cross-sectional area less than that of said gas flow passage.

5. Particulate material conveying apparatus as claimed in claim 4, wherein said constriction passage is formed in a constrictor extending along part of said gas discharge passage, said constrictor and the wall of said gas discharge passage defining therebetween a space connecting said compressed gas outlet with one end of said constrictor, means being provided for preventing flow of the gas between the wall of said gas discharge passage and said constrictor to the other end of said constrictor.

6. Particulate material conveying apparatus as claimed in claim 5, wherein said constrictor comprises a tube extending along said gas discharge passage and spaced inwardly of the wall of said gas discharge passage from said compressed gas outlet to said one end of said constrictor.

7. Particulate material conveying apparatus as claimed in claim 4, further comprising means defining a powder collection space at the inlet end of said constriction passage.

8. Particulate material conveying apparatus as claimed in claim 1, wherein said vibrator means and said gas flow passage are provided in a common body, and said body has on its exterior a downwardly convergent tapered undersurface.

9. Particulate material conveying apparatus as claimed in claim 8, wherein said body is formed of two separate parts secured together with said ball race housed therebetween.

10. Particulate material conveying apparatus as claimed in claim 9, further comprising a gas flow tube through which said gas flow passage extends, said gas flow tube extending through said body and abutting one of said parts of said body, and a retainer in abutment with the other part of said body and secured to said gas flow tube, whereby said two body parts are secured together.

11. Particulate material conveying apparatus as claimed in claim 8, further comprising a tube projecting from said body, said inlet comprising an inlet passage extending through said tube, and said tube having a tapered outer end.

12. Particulate material conveying apparatus as claimed in claim 1, wherein said inlet comprises a tube protruding from said apparatus and having a tapered outer end. 

1. Particulate material conveying apparatus, comprising: an inlet for the entry of particulate material into the apparatus; a gas flow passage extending past said inlet; means for vibrating said inlet comprising a ball race extending around and spaced outwardly from said gas flow passage and a ball adapted to be driven around said race; and a compressed gas supply passage communicating with said vibrator means for supplying compressed gas to said vibrator means to drive the ball around the race; said vibrator means having a compressed gas outlet communicating with said gas flow passage for discharging the compressed gas from said vibrator means along said gas flow passage past said inlet to thereby entrain the particulate material through said inlet into and along said gas flow passage.
 2. Particulate material conveying apparatus as claimed in claim 1, further comprising a nozzle, said inlet comprising an inlet passage extending through said nozzle from the mouth of said nozzle to said gas flow passage, the outer surface of said nozzle having an outer surface which is tapered and converges with said inlet passage at said nozzle mouth to form a thin annular edge around said mouth.
 3. Pariculate material conveying apparatus as claimed in claim 1, wherein a constriction is provided in said gas flow passage for increasing the speed of flow of the compressed gas past said inlet.
 4. Particulate material conveying apparatus as claimed in claim 3, wherein said constriction comprises a constriction passage extending along said gas flow passage to said inlet and having a cross-sectional area less than that of said gas flow passage.
 5. Particulate material conveying apparatus as claimed in claim 4, wherein said constriction passage is formed in a constrictor extending along part of said gas discharge passage, said constrictor and the wall of said gas discharge passage defining therebetween a space connecting said compressed gas outlet with one end of said constrictor, means being provided for preventing flow of the gas between the wall of said gas discharge passage and said constrictor to the other end of said constrictor.
 6. Particulate material conveying apparatus as claimed in claim 5, wherein said constrictor comprises a tube extending along said gas discharge passage and spaced inwardly of the wall of said gas discharge passage from said compressed gas outlet to said one end of said constrictor.
 7. Particulate material conveying apparatus as claimed in claim 4, further comprising means defining a powder collection space at the inlet end of said constriction passage.
 8. Particulate material conveying apparatus as claimed in claim 1, wherein said vibrator means and said gas flow passage are provided in a common body, and said body has on its exterior a downwardly convergent tapered undersurface.
 9. Particulate material conveying apparatus as claimed in claim 8, wherein said body is formed of two separate parts secured together with said ball race housed therebetween.
 10. ParticulAte material conveying apparatus as claimed in claim 9, further comprising a gas flow tube through which said gas flow passage extends, said gas flow tube extending through said body and abutting one of said parts of said body, and a retainer in abutment with the other part of said body and secured to said gas flow tube, whereby said two body parts are secured together.
 11. Particulate material conveying apparatus as claimed in claim 8, further comprising a tube projecting from said body, said inlet comprising an inlet passage extending through said tube, and said tube having a tapered outer end.
 12. Particulate material conveying apparatus as claimed in claim 1, wherein said inlet comprises a tube protruding from said apparatus and having a tapered outer end. 